San Francisco is one of the best cities in the country to go solar — despite what the fog might suggest. California’s generous net metering policies, high electricity rates, and strong solar incentive programs make the economics compelling for most SF homeowners. But before you sign a solar installation contract, there’s a critical step that many homeowners skip: making sure your roof can actually support a solar array for the next 25–30 years.

Why Your Roof Matters Before Going Solar

Solar panels have a lifespan of 25–30 years. If your roof is 15 years old when panels are installed, you’ll almost certainly need a roof replacement before the panels reach end of life — which means paying to remove and reinstall the panels to do the roof work. Solar panel removal and reinstallation typically costs $1,500–$4,000 depending on system size. If you’re going to need a new roof within the next 5–10 years, replacing it before your solar installation is significantly more economical than doing it after.

What Solar Installers Will (and Won’t) Tell You About Your Roof

Most solar installation companies are not roofing contractors. They will typically conduct a basic visual inspection of your roof and may require it to be in “good condition,” but their assessment is often superficial. They have a strong financial incentive to proceed with the sale — a roof problem that delays or prevents the installation is not in their interest to find. This is why we strongly recommend getting an independent roof inspection from a licensed roofing contractor before signing a solar contract.

Roof Age and Material Considerations

Different roofing materials interact with solar installations differently:

  • Asphalt shingles: The easiest and most common substrate for solar installation in San Francisco. Standard racking systems attach cleanly to asphalt shingles. If your asphalt roof is less than 10 years old and in good condition, you’re likely fine to proceed.
  • Tile roofs: Common on SF’s Mediterranean and Spanish Colonial homes. Solar installation on tile is more complex and expensive — tiles must be carefully removed and replaced around racking hardware, and the flashing is more intricate. Cracked tiles during installation are a real risk with inexperienced crews.
  • Flat roofs: Many SF Victorian flats have flat roof sections. Solar on flat roofs typically uses ballasted racking systems that don’t penetrate the membrane — but the membrane must be in excellent condition and able to handle the additional weight and foot traffic of ongoing maintenance.
  • Wood shake: Solar installation on wood shake is inadvisable. The material is brittle, fire-risk concerns are elevated, and most solar installers will decline to install on wood shake. If you have wood shake and want solar, plan for a roof replacement first.
  • Metal roofing: Excellent for solar — standing seam metal roofs can use clamp-based mounting systems that require no penetrations at all.

Structural Assessment

A standard residential solar installation adds approximately 2.5–4 lbs per square foot of dead load to your roof structure. For most California homes built to modern codes, this is within design tolerances. However, San Francisco has a large number of older homes — some over 100 years old — where the original roof framing may not have been designed to handle this additional load. Your solar installer should conduct (or commission) a structural assessment, particularly for older homes. If the framing needs reinforcement, that work needs to happen before panels are installed.

Permitting in San Francisco

Solar installations in San Francisco require permits from both the Department of Building Inspection (DBI) and the San Francisco Public Utilities Commission (SFPUC). California’s Solar Rights Act limits the ability of HOAs and local governments to block solar installations, but the permitting process still takes time — typically 2–6 weeks for residential systems in SF. Your solar installer should handle permitting, but confirm this is included in the contract and understand the timeline.

If your roof also needs replacement or repair work, those permits are filed separately and the roofing work should be inspected and closed out before solar installation begins — not concurrent with it.

The Right Sequence: Roof First, Solar Second

Our recommendation for any San Francisco homeowner considering solar:

  1. Get an independent roof inspection from a licensed roofing contractor (not the solar company).
  2. If the roof needs replacement or significant repairs, do that work first.
  3. Get the roofing permits closed and the work inspected.
  4. Then proceed with your solar installation on a sound, freshly warranted roof.

This sequence avoids the expensive scenario of needing to remove panels for roof work later, and ensures your solar warranty isn’t voided by subsequent roofing issues.

SF-Specific Incentives to Know

  • California Net Energy Metering (NEM 3.0): Allows you to sell excess solar generation back to PG&E. Rates were adjusted in 2023, but solar still makes strong economic sense for most SF homeowners.
  • Federal Solar Investment Tax Credit (ITC): A 30% federal tax credit on the total installed cost of your solar system, including any roof work done in preparation for solar installation.
  • GoSolarSF Program: San Francisco’s local solar incentive program, providing additional rebates for qualifying low-to-moderate income homeowners. Check sfenvironment.org for current program availability.

Eco Smart Roofer works regularly with solar installation companies across the Bay Area to prepare roofs for solar, coordinate sequencing, and ensure the roofing work is done right before panels go up. Contact us for a pre-solar roof assessment — we’ll give you an honest picture of your roof’s condition and what, if anything, needs to be done before your solar installation date.